Hello @Geoffrey59,

welcome to our o2 community
And thank you for your request!

My first question is - how did you pay your overdue bill?
You do not need to inform o2 about this. As soon as the money arrives, your contract will be reactivated if there were any restrictions due to the overdue invoice. It is important that if you have made a transfer, this can also be allocated to your customer account.

Kind regards
Jessica